A three-dimensional, colored, 60 volume element block model representing the neuronal structure of the superior olivary complex fo a cat's brain stem has been developed. The model allows rapid selection of a viewing surface computed for any selected cutting plane through the model volume. The model provides a common frame of reference for comparing anatomical and physiological data from different experimental animals. Investigators should be able to view a section of the "normal" cat on the same plane as the experimental sections and also along the plane described by various electode penetrations in the experimental animal. The model has been developed and used successfully on the Evans and Sutherland System. Publication-quality output has been produced. An atlas of over 150 views is being submitted to a medical journal.